from sys import stdin,stdout

def main():
    line=stdin.readline()
    parts=line.split()
    a=int(parts[0])
    if a>=30:
        stdout.write("Yes")
    else:
        stdout.write("No")
main() from sys import stdin,stdout def main():
    line=stdin.readline()
    parts=line.split()
    a=int(parts[0])
    if a>=30:
        stdout.write("Yes")
    else:
        stdout.write("No") main line=stdin.readline() line stdin.readline() stdin.readline stdin readline parts=line.split() parts line.split() line.split line split a=int(parts[0]) a int(parts[0]) int parts[0] parts 0 if a>=30:
        stdout.write("Yes")
    else:
        stdout.write("No") a>=30 a 30 stdout.write("Yes") stdout.write stdout write "Yes" stdout.write("No") stdout.write stdout write "No" main() main def main():
    line=stdin.readline()
    parts=line.split()
    a=int(parts[0])
    if a>=30:
        stdout.write("Yes")
    else:
        stdout.write("No") def main():
    line=stdin.readline()
    parts=line.split()
    a=int(parts[0])
    if a>=30:
        stdout.write("Yes")
    else:
        stdout.write("No") main
from sys import stdin,stdout

def main():
    line=stdin.readline()
    parts=line.split()
    a=int(parts[0])
    if a>=30:
        stdout.write("Yes")
    else:
        stdout.write("No")
main()